Let’s learn more about the tread pattern of our motorcycle tires
Unless it is a racing slick tire, tread patterns are a must for every DOT street tire. The tread design refers to the grooves in between the contact patch of the tire, this can also be called negative ratio. When a manufacturer like Continental develops a new motorcycle tire model, it focuses on the needs for the certain segment of that model. If it is a dual sport tire like the TKC 80, it will need to have certain design aspects and materials that tire needs to excel in its segment. Therefore, it will have a thick Bias-ply carcass with deep angular grooves to dig loose terrain and gain traction.
So why does every street tire should have a tread pattern?
Here are the main reasons:
Maintaining constant traction with the road surface in different conditions is essential for optimal performance and safety. In a perfectly smooth and dry road, no tread pattern, would be ideal. Unfortunately, this is only experienced in racing environments. But because road imperfections and wet surfaces, patterns are a must to guide the water out of the contact patch or let the tire gain traction in loose terrain.
It is important to remember that not only the suspension does all the work of absorbing the bumps, lateral or longitudinal G-forces, but also the tires. To do this, tires need to be flexible and mold partly around road surfaces. A tread pattern makes flexing easier while having a reasonable hard, durable rubber compound.
This is were the extremes of making a really grippy tire while still being DOT legal meet. A great example of this is the ContiRaceAttack End. Comp and the ContiAttack SM EVO. These tires try to get the maximum grip with little of a pattern as possible while still being road legal.
In a racing slick tire, wear is usually measured by the amount of grip that the rider feels and longer lap times. But it would be really hard for a commuter rider to measure wear the same way in real conditions. So this is another safety benefit that tread pattern brings. Grooves are needed to have tread wear indicators (TWI). TWI are the embedded divergent rubber lines in a certain place of the tire pattern. Once this TWI has the same level as the tread pattern, we know it is time to change the tire. The minimum tread wear mandated in the USA is 1/32 of an inch or .8 millimeters, TWIs are set to this measurement in the USA.
Despite all the function a certain tread pattern may have, you cant avoid the way it may end up looking. Tire looks can often form a big part of a motorcycle overall design as motorcycle tires are usually uncovered. The tread pattern also becomes a design characteristic of a brand and all manufacturers will try to stand out from each other by having interesting looking tread designs.
Now you know the main reasons why motorcycle tires and tires in general need a tread design in street applications. Stay tuned for part two of this post next week, this second part will delve deeper in the engineering and artistic aspect of tread designs.
Until next week!